<?php
namespace common\service;
use yii;
// 验证码类
class ValidateCodeService
{
    private $charset = 'abcdefghkmnprstuvwxyzABCDEFGHKMNPRSTUVWXYZ23456789'; // 随机因子
    private $code; // 验证码
    private $codelen = 4; // 验证码长度
    private $width = 130; // 宽度
    private $height = 50; // 高度
    private $img; // 图形资源句柄
    private $font; // 指定的字体
    private $fontsize = 20; // 指定字体大小
    private $fontcolor; // 指定字体颜色
                        // 构造方法初始化
    public function __construct ()
    {
        $webroot = yii::getAlias('@webroot');
        $this->font = $webroot . '/fonts/Roboto-BoldCondensedItalic-webfont.ttf'; // 注意字体路径要写对，否则显示不了图片
    }
    // 生成随机码
    private function createCode ()
    {
        $_len = strlen($this->charset) - 1;
        for ($i = 0; $i < $this->codelen; $i ++) {
            $this->code .= $this->charset[mt_rand(0, $_len)];
        }
    }
    // 生成背景
    private function createBg ()
    {
        $this->img = imagecreatetruecolor($this->width, $this->height);
        $color = imagecolorallocate($this->img, mt_rand(157, 255), 
                mt_rand(157, 255), mt_rand(157, 255));
        imagefilledrectangle($this->img, 0, $this->height, $this->width, 0, 
                $color);
    }
    // 生成文字
    private function createFont ()
    {
        $_x = $this->width / $this->codelen;
        for ($i = 0; $i < $this->codelen; $i ++) {
            $this->fontcolor = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
            imagettftext($this->img, $this->fontsize, mt_rand(- 30, 30), $_x * $i + mt_rand(1, 5), $this->height / 1.4, $this->fontcolor, $this->font, $this->code[$i]);
        }
    }
    // 生成线条、雪花
    private function createLine ()
    {
        // 线条
        for ($i = 0; $i < 6; $i ++) {
            $color = imagecolorallocate($this->img, mt_rand(0, 156), 
                    mt_rand(0, 156), mt_rand(0, 156));
            imageline($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $color);
        }
        // 雪花
        for ($i = 0; $i < 100; $i ++) {
            $color = imagecolorallocate($this->img, mt_rand(200, 255), mt_rand(200, 255), mt_rand(200, 255));
            imagestring($this->img, mt_rand(1, 5), mt_rand(0, $this->width),mt_rand(0, $this->height), '*', $color);
        }
    }
    // 输出
    private function outPut ()
    {
        header('Content-type:image/png');
        //ob_clean();
        ob_end_clean();
        imagepng($this->img);
        imagedestroy($this->img);
    }
    // 对外生成
    public function doimg ()
    {
        $this->createBg();
        $this->createCode();
        $this->createLine();
        $this->createFont();
        $this->outPut();
    }
    // 获取验证码
    public function getCode ()
    {
        return strtolower($this->code);
    }
}